Shelf



FIG. 1 is a perspective view of the shelf showing my design.

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a top view thereof;

FIG. 5 is a bottom view thereof;

FIG. 6 is a side view thereof; and,

FIG. 7 is an opposite side view thereof.

The broken line showing is included for the purpose of illustration andforms no part of the claimed design.

CLAIM The ornamental design for a shelf, as shown and described. 